Polymer‐anchored mononuclear and binuclear CuII Schiff‐base complexes: Impact of heterogenization on liquid phase catalytic oxidation of a series of alkenes

Liquid phase catalytic oxidation of a number of alkenes, for example, cyclohexene, cis‐cyclooctene, styrene, 1‐methyl cyclohexene and 1‐hexene, was performed using polymer‐anchored copper (II) complexes PS‐[Cu (sal‐sch)Cl] ( 5 ), PS‐[Cu (sal‐tch)Cl] ( 6 ), PS‐[CH₂{Cu (sal‐sch)Cl}₂] ( 7 ) and PS‐[CH₂{Cu (sal‐tch)Cl}₂] ( 8 ). Neat complexes [Cu (sal‐sch)Cl] ( 1 ), [Cu (sal‐tch)Cl] ( 2 ), [CH₂{Cu (sal‐sch)Cl}₂] ( 3 ) and [CH₂{Cu (sal‐tch)Cl}₂] ( 4 ) were isolated by reacting CuCl₂·2H₂O with [Hsal‐sch] ( I ), [Hsal‐tch] ( II ), [H₂bissal‐sch] ( III ) and [H₂bissal‐tch] ( IV ), respectively, in refluxing methanol. Complexes 1–4 have been covalently anchored in Merrifield resin through the amine nitrogen of the semicarbazide or thiosemicarbazide moiety. A number of analytical, spectroscopic and thermal techniques, such as CHNS analysis, Fourier transform‐infrared, UV–Vis, PMR, ¹³C‐NMR, electron paramagnetic resonance, scanning electron microscopy, energy‐dispersive X‐ray analysis, thermogravimetric analysis, atomic force microscopy, atomic absorption spectroscopy, and electrospray ionization‐mass spectrometry, were used to analyze and establish the molecular structure of the ligands ( I )–( IV ) and complexes ( 1 )–( 8 ) in solid state as well as in solution state. Grafted complexes 5 – 8 were employed as active catalysts for the oxidation of a series of alkenes in the presence of hydrogen peroxide. Copper hydroperoxo species ([Cu^III (sal‐sch)‐O‐O‐H]), which is believed to be the active intermediate, generated during the catalytic oxidation of alkenes, are identified. It was found that supported catalysts are very economical, green and efficient in contrast to their neat complexes as well as most of the recently reported heterogeneous catalysts.     

Visible‐Light‐Accelerated Copper(II)‐Catalyzed Regio‐ and Chemoselective Oxo‐Azidation of Vinyl Arenes

The visible‐light‐accelerated oxo‐azidation of vinyl arenes with trimethylsilylazide and molecular oxygen as stoichiometric oxidant was achieved. In contrast to photocatalysts based on iridium, ruthenium, or organic dyes, [Cu(dap)₂]Cl or [Cu(dap)Cl₂] were found to be unique for this transformation, which is attributed to their ability to interact with the substrates through ligand exchange and rebound mechanisms. Cu^II is proposed as the catalytically active species, which upon coordinating azide will undergo light‐accelerated homolysis to form Cu^I and azide radicals. This activation principle (Cu^II‐X→Cu^I+X^.) opens up new avenues for copper‐based photocatalysis.     

catena‐Poly­[[tetrakis(2‐allyl­tetrazole‐κN4)‐tetra‐μ‐chloro‐tricopper(II)]‐di‐μ‐chloro]

In the crystal structure of the title compound, [Cu₃Cl₆(C₄H₆N₄)₄]_n, there are three Cu atoms, six Cl atoms and four 2‐allyl­tetrazole ligands in the asymmetric unit. The polyhedron of one Cu atom adopts a flattened octahedral geometry, with two 2‐allyl­tetrazole ligands in the axial positions [Cu—N4 = 1.990 (2) and 1.991 (2) Å] and four Cl atoms in the equatorial positions [Cu—Cl = 2.4331 (9)–2.5426 (9) Å]. The polyhedra of the other two Cu atoms have a square‐pyramidal geometry, with three basal sites occupied by Cl atoms [Cu—Cl = 2.2487 (9)–2.3163 (8) and 2.2569 (9)–2.3034 (9) Å] and one basal site occupied by a 2‐allyl­tetrazole ligand [Cu—N4 = 2.028 (2) and 2.013 (2) Å]. A Cl atom lies in the apical position of either pyramid [Cu—Cl = 2.8360 (10) and 2.8046 (9) Å]. The possibility of including the tetrazole N3 atoms in the coordination sphere of the two Cu atoms is discussed. Neighbouring copper polyhedra share their edges with Cl atoms to form one‐dimensional polymeric chains running along the a axis.     

The layered structure of poly­[[di‐μ‐chloro‐bis­[chloro(2‐ethyl­tetrazole‐κN4)copper(II)]]‐di‐μ‐2‐ethyl­tetrazole‐κ2N1:N4]

In the polymeric title complex, [CuCl₂(C₃H₆N₄)₂]_n, there are two ligands in the asymmetric unit. The Cu atom adopts an elongated octahedral geometry, with two 2‐ethyl­tetrazole ligands [Cu—N = 2.0037 (16) and 2.0136 (16) Å] and two Cl atoms [Cu—Cl = 2.2595 (6) and 2.2796 (6) Å] in equatorial positions. A Cl atom and a symmetry‐related 2‐ethyl­tetrazole mol­ecule [Cu—Cl = 2.8845 (8) Å and Cu—N = 2.851 (2) Å] lie in the axial positions of the octahedron. One of the two 2‐­ethyltetrazole ligands of the asymmetric unit exhibits bidentate binding to two Cu atoms through two N atoms of the tetrazole ring, whereas the other ligand is coordinated in a monodentate fashion via one tetrazole N atom. The Cu‐atom octahedra form dimer entities by sharing edges with equatorial and axial Cl atoms. The dimers are linked together through the 2‐ethyl­tetrazole ligands to form one‐dimensional polymeric zigzag chains extending along the b axis. The chains are connected into infinite layers parallel to the (10) plane via the 2‐ethyl­tetrazole ligands.     

0-D and 1-D inorganic-organic composite polyoxotungstates constructed from in-situ generated monocopper-substituted Keggin polyoxoanions and copper-organoamine complexes

Combination of in-situ generated monocopper^II-substituted Keggin polyoxoanions with copper^II-organoamine complexes under hydrothermal conditions results in seven inorganic-organic composite polyoxotungstates [Cu(en)₂(H₂O)]₂{[Cu(en)₂][α-PCuW₁₁O₃₉Cl]}·3H₂O (1), {[Cu(en)₂(H₂O)][Cu(en)₂]₂[α-PCuW₁₁O₃₉Cl]}·6H₂O (2), {[Cu(en)₂(H₂O)]₂[Cu(en)₂][α-XCuW₁₁O₃₉]}·5H₂O (3/4, X=Si^IV/Ge^IV), {[Cu(deta)(H₂O)₂]₂[Cu(deta)(H₂O)][α-XCuW₁₁O₃₉]}·5H₂O (5/6, X=Ge^IV/Si^IV) and [Cu(dap)₂]₂{[Cu(dap)₂]₂[Cu(dap)₂][α-PCuW₁₁O₃₉]₂} (7) (en=ethylenediamine, dap=1,2-diaminopropane and deta=diethylenetriamine). 1 is an isolated structure whereas 2 is a 1-D chain structure, but both contain [α-PCuW₁₁O₃₉Cl]⁶⁻ polyoxoanions. 3-6 contain the 1-D linear chains made up of [α-XCuW₁₁O₃₉]⁶⁻ polyoxoanions in the pattern of -A-A-A- (A=[α-XCuW₁₁O₃₉]⁶⁻), while 7 demonstrates the first 1-D zigzag chain constructed from [α-PCuW₁₁O₃₉]₂¹⁰⁻ polyoxoanions via [Cu(en)₂]²⁺ bridges in the pattern of -A-B-A-B- (A=[α-PCuW₁₁O₃₉]₂¹⁰⁻, B=[Cu(en)₂]²⁺). The successful syntheses of 1-7 can provide some experimental evidences that di-/tri-/hexa-vacant polyoxoanions can be transformed into mono-vacant Keggin polyoxoanions under hydrothermal conditions.     

catena‐Poly­[[[cis‐bis(1‐phenyl­tetra­zole‐κN4)copper(II)]‐di‐μ‐chloro] hemi(1‐phenyl­tetrazole)]

The title compound, {[CuCl₂(PhTz)₂]·0.5PhTz}_n (PhTz is 1‐­phenyl­tetrazole, C₇H₆N₄), has a polymeric structure, with uncoordinated disordered PhTz mol­ecules in the cavities. The coordination polyhedron of the Cu atom is a highly elongated octahedron. The equatorial positions are occupied by two Cl atoms [Cu—Cl = 2.2687 (9) and 2.2803 (7) Å] and two N atoms of the PhTz ligands [Cu—N = 2.0131 (19) and 2.0317 (18) Å]. The more distant axial positions are occupied by two Cl atoms [Cu—Cl = 3.0307 (12) and 2.8768 (11) Å] that lie in the equatorial planes of two neighbouring Cu octahedra. The [CuCl₂(PhTz)₂] units are linked by Cu—Cl bridges into infinite chains extending parallel to the a axis. The chains are linked into two‐dimensional networks by intermolecular C—H⋯N interactions between the phenyl and tetrazole fragments, and by face‐to‐face π–π interactions between symmetry‐related phenyl rings. These two‐dimensional networks, which lie parallel to the ac plane, are connected by intermolecular π–π stacking interactions between phenyl rings, thus forming a three‐dimensional network.     

Structural Study of Nickel(II), Copper(II), and Palladium(II) Complexes of 2‐Pyridineformamide 3‐Hexamethyleneiminylthiosemicarbazone

Reduction of 2‐cyanopyridine by sodium in the presence of 3‐hexamethyleneiminylthiosemicarbazide produces 2‐pyridineformamide 3‐hexamethyleneiminylthiosemicarbazone, HAmhexim. Complexes with nickel(II), copper(II) and palladium(II) have been prepared and the following complexes structurally characterized: [Ni(Amhexim)OAc], [{Cu(Amhexim)}₂C₄H₄O₄]·2DMSO·H₂O, [Cu(HAmhexim)Cl₂] and [Pd(Amhexim)Cl]. Coordination is via the pyridyl nitrogen, imine nitrogen and thiolato or thione sulfur atom when coordinating as the anionic or neutral ligand, respectively. [{Cu(Amhexim)}₂C₄H₄O₄] is a binuclear complex with the two copper(II) ions bridged by the succinato group in [Cu‐(HAmhexim)Cl₂] the Cu atom is 5‐coordinate and close to a square pyramid structure and in [Ni(Amhexim)OAc] and [Pd(Amhexim)Cl] the metal atoms are planar, 4‐coordinate.     

catena‐Poly[[bis(cis‐1‐tert‐butyltetrazole‐κN4)copper(II)]‐di‐μ‐chloro]

The title polymeric compound, [CuCl₂(C₅H₁₀N₄)₂]_n, is the first structurally characterized complex with a bulky 1‐alkyl­tetrazole ligand. The coordination polyhedron of the Cu atom is an elongated octahedron. The equatorial positions of the octahedron are occupied by the two Cl atoms, with Cu—Cl distances of 2.2920 (8) and 2.2796 (9) Å, and by the two N‐4 atoms of the tetrazole ligands, with Cu—N distances of 2.023 (2) and 2.039 (2) Å. Two symmetry‐related Cl atoms occupy the axial positions, at distances of 2.8244 (8) and 3.0174 (8) Å from the Cu atom. The [CuCl₂(C₅H₁₀N₄)₂] units form infinite chains extended along the b axis, linked together only by van der Waals interactions. The skeleton of each chain consists of Cu and Cl atoms.     

Ir(III)‐Catalyzed C7‐Position‐Selective Oxidative CH Alkenylation of Indolines with Alkenes in Air

An efficient method for C7‐position‐selective alkenylation of N‐substituted indolines with alkenes is reported. Various 7‐alkenylindolines were obtained in moderate to excellent yields in air in the presence of catalytic amounts of [Cp*IrCl₂]₂, AgOTf, and Cu(OAc)₂. The protocol relies on the use of a carbonyl or carbamoyl group on the nitrogen atom of indoline as a directing group and is potentially applicable to the synthesis of 7‐alkenylindoles and 7‐alkylindoles.     

catena‐Poly­[[bis­[μ‐1,2‐bis(1‐methyl­tetrazol‐5‐yl)­ethane‐κ2N4:N4′]bis[chloro­copper(II)]]‐di‐μ‐chloro]

In the title compound, [Cu₂Cl₄(C₆H₁₀N₈)₂]_n, the ligand has C₂ symmetry, and the Cu and Cl atoms lie on a mirror plane. The coordination polyhedron of the Cu atom is a distorted square pyramid, with the basal positions occupied by two N atoms from two different ligands [Cu—N = 2.0407 (18) Å] and by the two Cl atoms [Cu—Cl = 2.2705 (8) and 2.2499 (9) Å], and the apical position occupied by a Cl atom [Cu—Cl = 2.8154 (9) Å] that belongs to the basal plane of a neighbouring Cu atom. The [CuCl₂(C₆H₁₀N₈)]₂ units form infinite chains extending along the a axis via the Cl atoms. Intermolecular C—H⃛Cl contacts [C⃛Cl = 3.484 (2) Å] are also present in the chains. The chains are linked together by intermolecular C—H⃛N interactions [C⃛N = 3.314 (3) Å].     

Copper Complexes with New Pyridylpyrazole Based Ligands

We report the synthesis, characterization, and crystal structures of new ligands of the pyridinylpyrazole type, i.e., 3,5‐bis(4‐butoxyphenyl)‐1‐(pyridin‐2‐yl)‐1H‐pyrazole ( L ¹ ) and 3,5‐bis(4‐phenoxyphenyl)‐1‐(pyridin‐2‐yl)‐1H‐pyrazole ( L ² ) (Scheme 1), and the study of their coordination behavior towards Cu^I and Cu^II. The versatility of this type of ligand, which can give access to different coordination spheres about the metal center, depending on the nature of the copper starting material used in the preparation of the complexes (Scheme 2), is illustrated. Thus, pseudo‐tetrahedral Cu^I as well as six‐coordinated tetragonal and distorted tetragonal pyramidal Cu^II derivatives were obtained for [Cu(L)₂]PF₆, [Cu(Cl)₂(L)₂] (L= L ¹ , L ² ), and [Cu(Cl)( L ¹ )₂]PF₆, respectively. We also present a crystallographic support of a distorted octahedral cis‐bis(tetrafluoroborato‐κF)copper(II) compound found for [Cu(BF₄)₂( L ¹ )₂] ( 3 ).     

Syntheses and Structures of Two Selenite Chloride Hydrates: Co(HSeO3)Cl · 3 H2O and Cu(HSeO3)Cl · 2 H2O

The first selenite chloride hydrates, Co(HSeO₃)Cl · 3 H₂O and Cu(HSeO₃)Cl · 2 H₂O, have been prepared from solution and characterised by single‐crystal X‐ray diffraction. The cobalt phase adopts an unusual “one‐dimensional” structure built up from vertex‐sharing pyramidal [HSeO₃]^2–, and octahedral [CoO₂(H₂O)₄]^2– and [CoO₂(H₂O)₂Cl₂]^4– units. Inter‐chain bonding is by way of hydrogen bonds or van der Waals' interactions. The atomic arrangement of the copper phase involves [HSeO₃]^2– pyramids and Jahn‐Teller distorted [CuCl₂(H₂O)₄] and [CuO₄Cl₂]^8– octahedra, sharing vertices by way of Cu–O–Se and Cu–Cl–Cu bonds. Crystal data: Co(HSeO₃)Cl · 3 H₂O, M_r = 276.40, triclinic, space group P 1 (No. 2), a = 7.1657(5) Å, b = 7.3714(5) Å, c = 7.7064(5) Å, α = 64.934(1)°, β = 68.894(1)°, γ = 71.795(1)°, V = 337.78(7) ų, Z = 2, R(F) = 0.036, wR(F) = 0.049. Cu(HSeO₃)Cl · 2 H₂O, M_r = 263.00, orthorhombic, space group Pnma (No. 62), a = 9.1488(3) Å, b = 17.8351(7) Å, c = 7.2293(3) Å, V = 1179.6(2) ų, Z = 8, R(F) = 0.021, wR(F) = 0.024.     

Crystal structure of bis(l-arginine)copper(II) hexachlorodimercurate, [Cu(l-Arg)2]Hg2Cl6

By means of X-ray diffraction the chain structure of [Cu(l-Arg)₂]Hg₂Cl₆ (monoclinic, a = 10.2348(9) Å, b = 9.1386(7) Å, c = 14.8521(14) Å, β = 97.455(11)°, space group P2₁) is established. The chains are formed by square-planar [Cu(l-Arg)₂]²⁺ cations of the type trans-[Cu(N)₂(O)₂] (l-Arg is the zwitter-ion of arginine; Cu-N 1.992 Å and 1.938(6) Å, Cu-O 1.953 Å and 1.967(4) Å) that are bonded to two adjacent binuclear [Cl₂Hg(μ-Cl)₂HgCl₂]^2? ions through its clorine atoms Cl (Hg-Cl bonds are within 2.34–2.78 Å). With these two additional Cu…Cl contacts Cu adopts the geometry of an elongated octahedron with two apical Cl (Cu-Cl 2.961 Å and 3.064(3) Å).     

4,4′‐Bi(1H‐pyrazol‐2‐ium) tetrachloridoaurate(III) chloride: a three‐dimensional cationic cooperite‐like framework with multiple pyrazolium–chloride hydrogen‐bonding interactions

In the title compound, (C₆H₈N₄)[AuCl₄]Cl, the 4,4′‐bi(1H‐pyrazol‐2‐ium) dication, denoted [H₂bpz]²⁺, is situated across a centre of inversion, the [AuCl₄]⁻ anion lies across a twofold axis passing through Cl—Au—Cl, and the Cl⁻ anion resides on a twofold axis. Conventional N—H...Cl hydrogen bonding [N...Cl = 3.109 (3) and 3.127 (3) Å, and N—H...Cl = 151 and 155°] between [H₂bpz]²⁺ cations (square‐planar node) and chloride anions (tetrahedral node), as complementary donors and acceptors of four hydrogen bonds, leads to a three‐dimensional binodal four‐connected framework with cooperite topology (three‐letter notation pts). The framework contains channels along the c axis housing one‐dimensional stacks of square‐planar [AuCl₄]⁻ anions [Au—Cl = 2.2895 (10)–2.2903 (16) Å; interanion Au...Cl contact = 3.489 (2) Å], which are excluded from primary hydrogen bonding with the [H₂bpz]²⁺ tectons.     

Structural Aspects of Copper‐Mediated Atom Transfer Radical Polymerization with a Novel Tetradentate Bisguanidine Ligand

This contribution reports the synthesis of the novel tetradentate bisguanidine ligand 2′,2′‐[ethane‐1, 2‐diylbis(methylazanediyl)]bis(ethane‐2, 1‐diyl)bis(1, 1, 3, 3‐tetramethylguanidine) ( L1 , TMG₂dmtrien), which combines two weak amine and two strong guanidine donor functions. Two new copper(II) complexes were isolated and structurally characterized as complexes [Cu(TMG₂dmtrien)][Br]₂ · 3MeCN ( C1 [Br]₂ · 3MeCN) and [Cu(TMG₂dmtrien)][Cl]₂ · 3MeCN ( C2 [Cl]₂ · 3MeCN). The cations C1 and C2 [Cu(TMG₂dmtrien)]²⁺ show a square‐planar coordination environment and are chiral with both enantiomers being observed in the unit cell. We investigated the application of L1 in copper‐mediated styrene ATRP. L1 shows with CuBr and PEBr as initiator a high polymerization activity according to the polymerization rate. First order kinetics confirm the living character of the polymerization. However, the deviation of molecular weights from theoretical molecular weights and the broad molecular weight distributions hint for a low controlled ATRP. The ATRP with further copper(I) salts {CuCl, [Cu(MeCN)₄]BF₄ and [Cu(MeCN)₄]PF₆} and PECl and PEBr as initiators were investigated as well. Herein the use of [Cu(MeCN)₄]PF₆ with PECl led to promising results.     

Cu(II)‐promoted cyclization of hydrazonophthalazine to triazolophthalazine; Synthesis and structure diversity of six novel Cu(II)‐triazolophthalazine complexes

A novel route for the synthesis of Cu(II)‐triazolophthalazine complexes using the Cu(II)‐promoted cyclization dehydrogenation reactions of hydrazonophthalazines under reflux was presented. Two hydrazonophthalazines were cyclized to the corresponding triazolophthalazine ligands, 3‐pyridin‐2‐yl‐3,10b‐dihydro‐[1,2,4]triazolo[3,4‐a]phthalazine ( TPP ) and 3‐(3,10b‐dihydro‐[1,2,4]triazolo[3,4‐a]phthalazin‐3‐yl)‐benzoic acid ( TP3COOH ), followed by in situ complexation with Cu(II) yielding six novel Cu(II)‐triazolophthalazine complexes depending on the reaction conditions. The molecular and supramolecular structures of the Cu(II)‐triazolophthalazine complexes were discussed. The metal sites have rectangular pyramidal geometry in the [Cu(TPP)Cl₂]₂; 1 and [Cu(TP3COOEt)Cl₂(H₂O)]₂; 4 dinuclear complexes, distorted square planar in [Cu(TP3COOMe)₂Cl₂]; 3 , [Cu(TP3COOH)₂Cl₂]; 5 and [Cu(TP3COOH)₂Cl₂]·H₂O; 6 and a distorted octahedral in [Cu(TPP)(H₂O)₂(NO₃)₂]; 2 . Hirshfeld analysis showed that the O…H, C…H, Cl…H (except TP3COOH and 2 ), N…H and π‐π stacking interactions are the most important intermolecular contacts. The π‐π stacking interactions are the maximum for TP3COOH and complex 6 with net C…C/C…N contacts of 19.4% and 15.4%, respectively. The orbital–orbital interaction energies of the Cu‐N/Cu‐Cl bonds correlated inversely with the corresponding Cu‐N/Cu‐Cl distances, respectively. The charge transfer processes between Cu(II) and ligand groups were also discussed. The charge densities of the Cu(II) centers are reduced to 0.663–0.995 e due to the interactions with the ligand groups coordinating it.     

Solvothermal Synthesis of two 2‐D Thioantimonates(III) with Metal Complexes as Template Ions, [M(dap)3]Sb4S7 (M = Ni2+ and Co2+)

Two new thioantimonates [M(dap)₃]Sb₄S₇ (M = Ni²⁺ ( 1 ) and Co²⁺ ( 2 )) were synthesized under solvothermal conditions by the reaction of NiS (or Co metal), Sb and S in an aqueous solution of 1,2‐diaminopropane (dap). Compounds 1 and 2 are isostructural. The polymeric [Sb₄S₇^2?]_n anion is composed of two SbS₃ trigonal pyramids and two SbS₄ units. The SbS₃ and SbS₄ units are interconnected by corners and edges to build a 2‐D puckered layer with Sb₄S₄ and Sb₁₆S₁₆ heterorings. The apertures of the large Sb₁₆S₁₆ hetero‐rings are filled by two [M(dap)₃]²⁺ complex cations which serve as template ions. The band gaps of 2.44 eV for 1 and 2.43 eV for 2 have been estimated from optical absorption spectra.     

Unusual 4‐arsonoanilinium cationic species in the hydrochloride salt of (4‐aminophenyl)arsonic acid and formed in the reaction of the acid with copper(II) sulfate,copper(II) chloride and cadmium chloride

Structures having the unusual protonated 4‐arsonoanilinium species, namely in the hydrochloride salt, C₆H₉AsNO₃⁺·Cl⁻, (I), and the complex salts formed from the reaction of (4‐aminophenyl)arsonic acid (p‐arsanilic acid) with copper(II) sulfate, i.e. hexaaquacopper(II) bis(4‐arsonoanilinium) disulfate dihydrate, (C₆H₉AsNO₃)₂[Cu(H₂O)₆](SO₄)₂·2H₂O, (II), with copper(II) chloride, i.e. poly[bis(4‐arsonoanilinium) [tetra‐μ‐chlorido‐cuprate(II)]], {(C₆H₉AsNO₃)₂[CuCl₄]}_n , (III), and with cadmium chloride, i.e. poly[bis(4‐arsonoanilinium) [tetra‐μ‐chlorido‐cadmate(II)]], {(C₆H₉AsNO₃)₂[CdCl₄]}_n , (IV), have been determined. In (II), the two 4‐arsonoanilinium cations are accompanied by [Cu(H₂O)₆]²⁺ cations with sulfate anions. In the isotypic complex salts (III) and (IV), they act as counter‐cations to the {[CuCl₄]²⁻}_n or {[CdCl₄]²⁻}_n anionic polymer sheets, respectively. In (II), the [Cu(H₂O)₆]²⁺ ion sits on a crystallographic centre of symmetry and displays a slightly distorted octahedral coordination geometry. The asymmetric unit for (II) contains, in addition to half the [Cu(H₂O)₆]²⁺ ion, one 4‐arsonoanilinium cation, a sulfate dianion and a solvent water molecule. Extensive O—H…O and N—H…O hydrogen bonds link all the species, giving an overall three‐dimensional structure. In (III), four of the chloride ligands are related by inversion [Cu—Cl = 2.2826 (8) and 2.2990 (9) Å], with the other two sites of the tetragonally distorted octahedral CuCl₆ unit occupied by symmetry‐generated Cl‐atom donors [Cu—Cl = 2.9833 (9) Å], forming a two‐dimensional coordination polymer network substructure lying parallel to (001). In the crystal, the polymer layers are linked across [001] by a number of bridging hydrogen bonds involving N—H…Cl interactions from head‐to‐head‐linked As—O—H…O 4‐arsonoanilinium cations. A three‐dimensional network structure is formed. Cd^II compound (IV) is isotypic with Cu^II complex (III), but with the central CdCl₆ complex repeat unit having a more regular M —Cl bond‐length range [2.5232 (12)–2.6931 (10) Å] compared to that in (III). This series of compounds represents the first reported crystal structures having the protonated 4‐arsonoanilinium species.     

Syntheses and Characterization of New Copper Complexes with the Heterocyclic Thione,AMTTO. X‐Ray Structures of [Cu(AMTTO)Cl2], [Cu(AMTTO)2]Cl,and [Cu(AMTTO)(PPh3)2Cl] (AMTTO = 4‐Amino‐6‐methyl‐1, 2, 4‐triazine‐3‐thione‐5‐one)

The complexes [Cu(AMTTO)Cl₂] ( 2 ), [Cu(AMTTO)₂]Cl ( 3 ), and [Cu(AMTTO)(PPh₃)₂Cl] ( 4 ) have been prepared and characterized by IR spectroscopy and elemental analyses. Also single‐crystal X‐ray diffraction studies on compound 2 , 3 and 4 revealed that AMTTO acts in 2 as a bidentate ligand via nitrogen and sulfur atoms, in 3 and 4 as a monodentate via sulfur atoms. Complex 3 was already mentioned in literature, but the structure was not described in detail. The molecules in 2 form infinite chains through additional weak Cu—S interactions along [010] indicating the Jahn‐Teller distortion of the d⁹ ion Cu²⁺. The infinite chains are connected by hydrogen bonding along [100]. Crystal data for 2 at —80°C: monoclinic, space group P2₁/m, a = 666.7(1), b = 609.4(1), c = 1132.6(2) pm, b = 95.46(2)°, Z = 2, R₁ = 0.0365; for 3 at —80°C: orthorhombic, space group Pbcn, a = 1291.2(2), b = 1146.5(1), c = 1000.5(1) pm, Z = 4, R₁ = 0.0315; for 4 at —80°C: monoclinic, space group, P2₁/n, a = 879.4(1), b = 1849.3(2), c = 2293.8(3) pm, β = 92.38(1)°, Z = 4, R₁ = 0.0688.